• Nutrient broth powder
  • Spatula
  • Weighing boat
  • Weighing scales
  • Deionised/distilled water
  • Measuring cylinder
  • Universal bottles and lids (or other container e.g. conical flask for growth medium)
  • Beaker
  • Magnetic stirrer
  • 10 cm3 pipette/syringe
  • Autoclave tape
  • Water bath
  • Marker pen
  • Eye protection
  • Heat resistant gloves


  1. Wear a lab coat and use eye protection. Wear protective gloves when handling hot equipment.
  2. Label universals or other container.
  3. Add the appropriate quantity of powder to the required volume of deionised/distilled water (see manufacturer’s instructions).
  4. Dissolve powder in the deionised/distilled water in a beaker (use a magnetic flea if possible).
  5. Dispense appropriate quantities (10 cm3 volumes into universals, larger volumes into conical flasks).
  6. Place caps on, tighten then loosen half a turn to allow steam penetration during sterilisation. If working with conical flasks, make a cotton wool bung and cover it with aluminium foil.
  7. Autoclave at 121°C for 15 minutes.
  8. Tighten caps when cool.

Note: for safety reasons, volumes of liquid medium should normally be kept to 10 cm3. Larger volumes e.g. in conical flasks would be used only for study of batch culture or as starter cultures for a small fermenter (bioreactor).